1. Field of Invention
This invention relates to vehicle differential units in which drive is transmitted from an input or drive pinion to a crown wheel and associated bevel pinions mounted in a cage carried by the crown wheel and hence to two output bevel gears which mesh with the bevel pinions and which are arranged to be attached to two output or half-shafts which extend one on each side of the crown wheel. The invention is exclusively concerned with such differential units in which the drive pinion is "straddle mounted".
The term "straddle mounted" as used throughout this specification is intended to cover differential units in which the drive pinion is mounted on a shaft supported on two axially spaced bearing assemblies carried by a housing which encloses the differential, the bearing assemblies being positioned one on each side of the drive pinion and comprising a first or outer bearing assembly supporting a first or outer end portion of the shaft with which the vehicle drive shaft is normally associated and a second or inner bearing assembly supporting a second or inner end portion of the shaft which is located within the housing adjacent the crown wheel.
2. Description of Prior Art
Heretofore, the inner bearing assembly has been supported on an internal flange which is an integral part of the housing of the differential unit. This has posed several problems as it has been found necessary, in order to assemble such a unit, to mount the outer bearing assembly in a detachable cartridge which is received in an aperture in the housing, the outer diameter of the cartridge being at least equal to the largest diametral measurement of the drive pinion in order that, with the drive pinion, shaft, outer bearing assembly and cartridge as an assembled unit, the drive pinion and inner portion of the shaft can be inserted into the housing via the aperture in which the cartridge is received. The procedure employed for mounting a drive pinion in such a unit is to press the inner bearing assembly into an aperture provided in the internal flange and then to insert the drive pinion, shaft, outer bearing assembly and cartridge as a unit into the aperture in the casing designed to receive the cartridge, while ensuring that the inner end portion of the shaft is received in the inner bearing assembly.
While such units have proved satisfactory in service, they are heavier than is necessary from a purely structural point of view, as the outer diameter of the cartridge is determined by the size of the drive pinion and is thus larger than is required in order to give adequate strength,
It is an object of the present invention to provide an improved form of vehicle differential unit employing a straddle mounted drive pinion.